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Montana Field Guide

Montana Field Guides

Johnston's Knotweed - Polygonum sawatchense
Other Names:  Polygonum douglasii ssp. johnstonii

Status Under Review

Global Rank: GNR
State Rank: SNR

Agency Status
USFWS:
USFS:
BLM:
MNPS Threat Rank:
C-value:

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General Description
Annual. Stems erect, simple or branched at the base, 5–35 cm. Leaves short-petiolate; blades 8–20 mm long, linear-oblong, reduced above; stipules lacerate, 2–10 mm long. Flowers 3–4 mm long, 1 to 4 in leaf axils; pedicels erect, 1–4 mm long; tepals green with white to pink margins. Achene 3-sided, 2–3 mm long, shiny black (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Species Range
Present
 


Range Comments
BC to SK south to CA, AZ and NM. One collection from an alpine, stony, calcareous slope in Beaverhead County (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Summary of Observations Submitted for Montana
Number of Observations: 1

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Habitat

References
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Citation for data on this website:
Johnston's Knotweed — Polygonum sawatchense.  Montana Field Guide.  .  Retrieved on , from